# L-functions of tempered automorphic representations

Let $$G$$ be a reductive group over the adele ring $$\mathbb A_F$$ of a number field $$F$$. Let also $$r$$ be a complex finite dimensional representation of the $$L$$-group $$r:{^LG}\to GL(V)$$.

It is generally known that for a tempered automorphic representation $$\pi = \otimes ' \pi_v$$ (meaning that the local constituents $$\pi_v$$ are tempered for all $$v$$), then the automorphic $$L$$-function $$L(s,\pi,r)$$ is holomorphic for Re$$(s)>1$$. But is there a good, concrete reference for this that I may cite for this? Or perhaps the proof of this is much easier than I am expecting?